No abstract

In this paper, a new species from Central China, Amana hejiaqingii (Liliaceae), is described and illustrated. It resembles A. anhuiensis and A. tianmuensis but differs from A. anhuiensis as it has one white vein on its lower leaf and yellow anthers. It also differs from A. tianmuensis by possessing solitary pink flowers with longer and wider tepals. The principal coordinates analysis separated the three species based on morphological data. Cytological observation showed that A. hejiaqingii is diploid (2n = 2x = 24). Molecular phylogenetic analyses further supported its species delimitation.

Amana Honda (Liliaceae), known as ‘east Asian tulips’, is a spring ephemeral genus endemic to Sino-Japanese Floristic Subregion, mainly distributed in eastern and central China, Japan and the Korean peninsula. Chromosome numbers are reported here for the first time from 89 populations of Amana (representing all seven accepted species, two new species about to be published, and two suspected new species). Three ploidy levels are found in this genus. These are diploid (2n = 2x = 24) and tetraploid (2n = 4x = 48) in the widespread A. edulis, while all the narrow endemics are diploid, except for one population of A. tianmuensis, which is triploid (2n = 3x = 36). The northernmost and southernmost populations of A. edulis are diploid and tetraploid, respectively, while diploids and tetraploids coexist in between, with gradual transition to diploids as the latitude increases. This may indicate polyploids have an advantage in tolerance of environmental stress and are more adaptable to high-temperature environment in subtropical regions than diploids. The species and cytotype distributions in Amana are complex, and these results provide hypotheses about the origins of the genus and the polyploid cytotypes.